This pack of 2, Friedland Response alarms are ideal for detecting possible burglars in your home. These wall-mounted wireless units work up to a range of 12 metres, and can be used to secure large rooms, hallways and landings. The alarms detect movement with PIR motion detectors. Then a signal is sent to the alarm system. These Friedland Response alarms are compatible with the Premium range of alarm kits. Batteries are included. Compatible with the Standard 433MHz Wireless Alarm Systems with control panels.